I think fitting is interesting. Often times, it appears one could go do multiple fittings with different fitters on consecutive days and come away with different results each time.
That said, I do think there is benefit if even just ensure you’re in the right “ballpark” for launch, spin, shaft weight etc.
I definitely would agree that Driver is probably the most beneficial club to have fitted and in my experience, the one that has resulted in a significant improvement versus what I played prior to the fitting.
As other have stated, it also comes down to the fitter. If they’re just someone with a Trackman trying to get you an additional 15-20 yards on your 7i without care for any of the other data, that’s probably not going to translate effectively to the course.